In the ’70s and ’80s, Hitler was frequently a figure of fun – Freddie Starr, John Cleese and Mel Brooks all raised a laugh with their impressions, swastikas and all.

The noughties heralded a more censorious approach: members of the Royal Family and even MPs found themselves the target of widespread abuse for their choice of Wehrmacht chic.

Inexplicably, the move towards a more serious appreciation of the Nazi tyranny and the Holocaust they inflicted on Europe has coincided, at least among some politicians, with a baffling ignorance of that despicable regime’s actual record. Livingstone is a case in point.

It is true that Hitler and his generals flirted with the idea of removing Europe’s Jews to the Middle East where they could attempt re-establish their ancestral homeland.

They also considered Madagascar and various other destinations before settling on a grotesque combination of methodical extermination and exile to northern Russia (where it was expected the harsh conditions would eventually result in the same ends).

Given that Zionism at the time was a Jewish nationalist movement committed to the establishment and security of a State of Israel, it would be a stupid man indeed to describe Hitler as an adherent to that philosophy.

Comparison with Hitler and Nazism is the ultimate political insult. Its casual use became so frequent on social media that it encouraged Mike Godwin, an American lawyer, to promulgate his eponymous “law” that states that if any online discussion continues for long enough, someone will eventually and inevitably compare something or someone with Hitler.

If only such behaviour were confined to social media.

Student politicians and followers of various far Left outfits are particularly enthusiastic adherents of the Nazi insult; police officers, traffic wardens, MPs, corporations – any behaviour of which the critic disapproves can, in his mind, be justifiably compared with the worst, most bestial, most decadent and violent regime Europe has ever known.

But Livingstone isn’t the only mainstream politician to have used the “H” word without thought, analysis or appreciation of historical fact.

Earlier this month, the “Baby of the House”, Britain’s youngest MP, the SNP’s Mhairi Black, penned a newspaper column in which she claimed that the Conservative Party’s immigration policies were “reminiscent of early 1930s Nazi Germany”.

At last week’s SNP conference, Christina McKelvie MSP made the same claim, specifically with regard to Home Secretary Amber Rudd’s (admittedly ludicrous) proposal that UK companies should state how many of their workers are non-UK citizens. This, said Ms McKelvie, was “reminiscent of the Nazis”.

But the worst, most offensive, most inaccurate and most blatant smear came from a non-politician at the same conference.

Gregg Brain, an Australian whose family was almost deported from Scotland after they overstayed and broke the terms of their post-study work visa and who only elicited a U-turn from the Home Office after a clever and emotive PR campaign, proudly wore a yellow badge with the letter “F” on it as he took to the stage in Glasgow. This, Mr Brain told delirious delegates, was “a response to Amber Rudd’s programme”.

A yellow badge. Denoting his alien status.

Gregg Brain makes a speech at the SNP conference in Glasgow on the "horrific" battle his family endured to be allowed to stay in the countryCredit:
Jane Barlow/PA

What could possibly be offensive about that?

What Mr Brain and his new friends in the SNP fail, perhaps deliberately, to understand is that comparing modern, democratic governments to the Nazis, while naturally giving the offence intended, also denigrates the victims of the actual regime which is being used in the comparison.

Jews living in Nazi-occupied Europe were not subjected to seemingly needless bureaucracy and given 30 days’ notice to leave the country or face further fines.

They were not politely but firmly informed that unless they secured full time employment, their immigration status couldn’t be guaranteed, and they were certainly not indulged by the media to broadcast their grievances and encourage popular support for their plight.

No, Jews in Nazi-occupied Europe were beaten, tortured, raped, deported and executed. They were deprived of their employment, their possessions, their dignity and, ultimately, their lives.

They were not invited to address rival parties’ conferences in order to denounce the very politicians who had used their ministerial discretion to allow them to stay in the country for another year.